Emma Watson is opening up about those adorable Harry Potter and the Sorcerer’s Stone outtakes that show her inadvertently mouthing her co-stars – Daniel Radcliffe and Rupert Grint – lines during filming.

While making an appearance on Jimmy Kimmel Live on Monday (March 6) in Los Angeles, the 26-year-old admitted that the whole experience was “quite traumatic” for her.

“You laugh, this is actually quite traumatic for me because I created issues because of this,” Emma revealed to Jimmy. “Yes, I would ruin takes. [Director] Chris [Columbus] would be like, ‘Cut. Emma, you’re doing it again. You’re mouthing Dan’s lines,’ and I’d be like, ‘Ooo, I’m so sorry, so sorry. Oh, I feel so bad.’ But I couldn’t help myself.”

“I was such a loser, I really loved those books, I really wanted to do my job well, and I kind of overdid it,” Emma joked.

Emma also talked about being a book ninja and promoted Beauty and the Beast.